This research is based on practice and is the first academic investigation of the methodology of Open Source Theatre (OST). OST is a form of advocacy. It is built on the concerns, experiences and vision of the subject group with the cooperation of representatives from the range of stakeholders. New roles are identified: the Initiator, the Precipitator and in particular the Arbitrator, not dissimilar to the traditional role of Director but stripped of any power over content. Their collaboration, in the Integrated Team, protects the process from insidious dominances. OST increases input from the subject group in the theatre-making process by altering the power balance. It is a response to the constraints and challenges of democracy. I will argue that it combats the habitual silences of apathy and fear and that it counters manipulation from the powerful. The essence is a distillation of fact and fiction in the surfeit of information surrounding us. This encourages the production of information-dense 'snapshots' (or dramatised sound-bites) that concentrate the audience's attention. Definitions of applied theatre sideline OST, in part because the subject group is rarely the target audience. Responding to an often-frustrated desire among the disenfranchised to be given a hearing, OST typically seeks an audience in a wider sphere, albeit sometimes a smaller but more specific and, ideally, more influential one. I will argue that OST processes are complementary to, though distinct from, those used in other forms of theatre for social change. The hypothesis is that impeding the devising team's freedom mobilises the subject group. It is the subject group who set the agenda, approve the critical analysis and validate the drama: they become creative agents rather than donors.